1. Field of the Invention
This invention relates to clamping devices, and in particular to a pneumatically operated device which is adapted to assembly operations of printed circuits in which the clamping device has two degrees of motion which provide clear access to a work area when the device is in an unclamped position.
2. Description of Related Art
Assembly operations require the accurate placement and retention of parts relative to one another. Efficient assembly operations also require the rapid movement of these parts into and away from the assembly work area. Clamping tools which retain the parts in a predetermined position can interfere with the rapidity of the assembly operation if: they remain in the way of the next part to be assembled, or if they disturb the predetermined location of the part as it is clamped. In the electronics industry, the parts to be assembled continue to be more densely packed with finer conductors, thinner insulators, and more critical mechanical tolerances. These parts are also more easily damaged. So there are conflicting requirements placed upon clamping devices to increase throughput, work with tighter tolerances, and protect delicate assemblies.
For the assembly of printed wiring boards, which increasingly have multiple layers of conductors interleaved with insulators, component leads are inserted into holes drilled into the printed wiring board or they are surface mounted to pads which are solder and rosin coated. Either way, the predetermined location of the printed wiring board can not be changed as the clamp is applied. Therefore, the clamp must be applied with a linear motion so as not to twist the printed wiring board. However, a clamp with only a single degree of motion is likely to impede the rapid insertion and removal of the printed wiring board from the assembly position.
Accordingly, there is a need in the assembly art for a clamping device which is compact, which retains the accurate placement of the printed wiring board as the clamp is applied, which has two degrees of motion as the clamp is released so that easy access is provided for insertion of the next printed wiring board, and which does not damage delicate electronic structures.